Install
apt-get install kvm vde2 kvm-source libvirt-bin
Create guest image
mkdir -p /var/kvm/guests/disks
qemu-img create -f qcow2 /var/kvm/guests/disks/win7pro.disk.img 10G
Install guest
qemu-system-x86_64 -hda /var/kvm/guests/disks/win7pro.disk.img -cdrom /path/to/installation/image/SW_DVD5_Win_Pro_7_32BIT.ISO
Extend a disk-image
if i want to add additional 5 GB to my existing disk:
cd /path/to/imagedir/
qemu-img create -f raw add.img 5G
creates an emty image of 5 GB size
now cat the files…
cat originalDISK.img add.img >> newDISK.img
mv originalDISK.img originalDISK.img.backup
mv newDISK.img originalDISK.img
start the vm and use onboard tools to extend your partitions…
…have fun 😉